Mobo fan problem

hey all,
i started my desktop up today and got a nasty sound out of my computer, after a bit of digging i found out its my northbridge cooling fan (i think, its the only fan on the mobo besides my cpu fan). i disassembled it and otherwise messed with it to make it go away, and as long as its unscrewed from the heatsink it seems ok (sound is like the blades are hitting something, but it looks like it has clearance everywhere), but as soon as i put it back it starts again. so, twofold question, am i right to suspect that its thrown a bearing and is essentially dead and can i safely run my system with just the heatsink. i have decent and its right next to my cpu sink which stays pretty cool and theres an outlet fan about 4 inchs from it. it is also however very close to my 9800gtx+, which does run fairly cool but its the newest part of my system and i don't want to frag it.
i can't afford a new mobo right now, though i have been looking into it so whatever the fix i think it only needs to last for 6 months or so.

i've managed to get the fan limping along, if i use speedfan to lower the rotation rate its merely a little loud (still drowned out by my 9800gtx at 70% which is acceptable). i'm not sure if a standard 40mm would fit, its got a kinda odd install, it screws directly into the heatsink and sits in a depression that seems designed for it. (if i res the thread for more help i'll provide a pic). thanks for the advice and when the time comes to old yeller it hopefully i'll be able to find a replacement of some sort (molex pin idea is good or maybe i can scavenge something from an old mobo...)